Function esp_idf_sys::spi_get_freq_limit

pub unsafe extern "C" fn spi_get_freq_limit(
    gpio_is_used: bool,
    input_delay_ns: c_int
) -> c_int

@brief Get the frequency limit of current configurations. SPI master working at this limit is OK, while above the limit, full duplex mode and DMA will not work, and dummy bits will be aplied in the half duplex mode.

@param gpio_is_used True if using GPIO matrix, or False if native pins are used. @param input_delay_ns Input delay from SCLK launch edge to MISO data valid. @return Frequency limit of current configurations.